ExUnit Code Review

Quick Reference

Issue Type Reference

Async tests, setup, describe, tags references/exunit-patterns.md

Behavior-based mocking, expectations references/mox-boundaries.md

Bypass, Swoosh, Oban testing references/test-adapters.md

What to mock vs real, Ecto sandbox references/integration-tests.md

Mock Boundary Philosophy

Mock at external boundaries:

• HTTP clients, external APIs, third-party services

• Slow resources: file system, email, job queues

• Non-deterministic: DateTime.utc_now(), :rand

DO NOT mock internal code:

• Contexts, schemas, GenServers

• Internal modules, PubSub

• Anything you wrote

Review Checklist

Test Structure

• Tests are async: true unless sharing database state

• Describe-blocks group related tests

• Setup extracts common test data

• Tests have clear arrange/act/assert structure

Mocking

• Mox used for external boundaries (HTTP, APIs)

• Behaviors defined for mockable interfaces

• No mocking of internal modules

• verify_on_exit! in setup for strict mocking

Test Adapters

• Bypass for HTTP endpoint mocking

• Swoosh.TestAdapter for email testing

• Oban.Testing for background job assertions

Database

• Ecto.Adapters.SQL.Sandbox for isolation

• Async tests don't share database state

• Fixtures/factories used consistently

Valid Patterns (Do NOT Flag)

• Mock in unit test, real in integration - Different test levels have different needs

• Not mocking database in integration tests - Database is internal

• Simple inline test data - Not everything needs factories

• Testing private functions via public API - Correct approach

Context-Sensitive Rules

Issue Flag ONLY IF

Not async Test actually needs shared state

Missing mock External call exists AND no mock/bypass

Mock internal Module being mocked is internal code

Before Submitting Findings

Use the issue format: [FILE:LINE] ISSUE_TITLE for each finding.

Load and follow review-verification-protocol before reporting any issue.